. you say that this is unsound science and potentially could lead to problems. why do you believe that there is not a value in at least looking at this gunman's dna? >> well, first of all, let me say that my heart goes out to all the people in newtown, connecticut. this was an horrific series of events. second of all, the major problem that i have as a geneticist is that it's impossible to gain much information with the sample size of one. so what you are looking at is one person's dna, and you're trying to say that it's different than other people. but you only have a sample size of one. >> would it be helpful, do you think, to look at the dna of other shooters of those from previous mass shootings? >> well, again, the problem is, we have probably less than five or even ten people that we're talking about. when studies -- accurate genetic studies are done on a whole population, we look for hundreds of different people, and you have to show a strong correlation with that. and the second problem would be what are we trying to look for? i mean, we're going -- the whole idea is you'r